How Does Facebook Make Money?

Facebook revenues reached $500 million in 2009, up from $300 million in 2008, according to Fortune editor David Kirkpatrick, who cites "well-informed sources" in his upcoming book, The Facebook Effect.

Facebook expects revenues to reach $800 million in 2010.

Where did 2009’s $500 million come from?

Self-service ads, which appear on the right side of the screen on Facebook, accounted for about $250 million to $300 million. They look like this: